Oil burner control system



Jan., 29, 1957 D. J. MUNROE 2,779,347

OIL BURNER CONTROL. SYSTEM Filed June 50, 1952 United OIL BURNER CONTROLSYSTEM David J. Munroe, Racine, Wis., assignor to Webster ElectricCompany, Racine, Wis., a corporation of Delaware This invention relatesto an oil burner system and, more particularly, to an improved systemfor controlling Vthe operation of an oil burner.

Although the use of a by-pass nozzle in a fuel oil burner has manydesirable features, it is subject to certain inherent design limitationswhich make it diliicult to utilize such. a nozzle in conjunction with ahigh pressure oil supply system. Prior systems utilizing a by-passnozzle supply high pressure oil to the nozzle before a control valve inthe by-pass system of the nozzle opens with the consequent result thatsolid oil is injected into the tire chamber. Also, many existing systemsutilize a control valve in the by-pass system which is closed prior toclosing the valve controlling the supply of high pressure oil to thenozzle whereby large amounts of solid oil are injected into the tirechamber with its attendant disadvantages.

Further, since the bach pressure produced in the bypass line from thenozzle is relatively small in magnitude, it is impossible to utilize`self regulating valves therein which are capable of high seatingpressures upon closure so that it is impossible to provide a fluid-tightseal between a by-pass reservoir or suction side of the fuel pump andthe by-pass portion of the nozzle. The existing oil burner systemsutilizing a by-pass nozzle also provide a plurality ot separate controlvalves for the supply line and the by-pass line with a consequentincrease in the installation space required. Because of the dependencyof the existing systems on back pressure for controlling the operationof the luy-pass control valve, it is impossible to provide a controlvalve for the by-pass line which is operated independently of the backpressure in this line and which is also positively operated in apredetermined sequence with respect to the operation of the controlvalve in the line supplying oil to the nozzle.

Accordingly, one object of this invention is to provide a control valvesystem for an oil burner in which the bypass line from the nozzle isopened prior to opening a valve in the supply line for the nozzle whenthe pump for the oil burner is actuated.

Another object of this invention is to provide a new and improvedcontrol valve system for an oil burner in which the fuel supply line tothe nozzle is closed before the by-pass line when the pump or the oilburner is stopped. v

A still further obg'ect involves the provision of a unitary controlvalve assembly which is small in size and easily `installed inconjunction with the associated fuel oil burner equipment.

`Another object of this invention is to provide a control valve for theby-pass line of a by-pass nozzle which is positively operated in adesired sequence relative to the operation of a valve controlling theadmission of high pressure oil to said nozzle.

v A further object is to provide a control valveassembly Ifor theby-pass line of Ia by-pass nozzle in which the operationof the by-passcontrol valverelative to the opertes Patent" ice 2, ation of a controlvalve in the fuel supply line is inde pendent of the back pressureproduced in the by-pass line' by said nozzle.

ln accordance with these and many other objects, one embodiment of thisinvention comprises an oil burner nozzle having a fuel supply line and aby-pass line which are each provided with control valves therein. Thesetwo control valves are combined into a unitary apparatus together with apressure regulator valveso that upon an increase in pressure of the fueloil supplied to the unitary assembly, a flexible diaphragm is movedupwardly to allow a spring loaded valve in the by-pass line to open. Theby-pass valve is mechanically interconnected with a valve in 'the .fuelsupply line so that upon reaching a predetermined position, the fuelsupply valve is opened to admit oil to the nozzle. A further increase inthe pressure of the oil supplied to the unitary assembly opens anotherlay-pass line from the valve assembly to an external reservoir so thatthe nozzle is supplied with fuel oil under a predetermined highpressure. When the pumping means supplying the fuel oil is stopped, thedecrease in pressure allows a spring loaded diaphragm to actuate themechanical interconnection between the twocontrol valves so that thevalve controlling the ilow of oil to the nozzle is closed and,subsequent thereto a continuing downward movement of the diaphragmactuates the spring loaded control element of the by-pass valve to closethe bypass line, thereby preventing the discharge of solid oil from thenozzle to fire chamber.

Other objects and advantages of the present invention will becomeapparent from the following description of an illustrative embodimentthereof in the course of which reference is made to the accompanyingdrawing wherein:

Fig. l is a schematic view of an oil burner system utilizing theimproved valve control assembly of this invention;

Fig. 2 is a fragmentary sectional view of a modication of the controlvalve assembly shown in Fig. l which may be utilized in conjunction withthe elements of the oil burner system disclosed in Fig. l;

Fig. 3 is a cross sectional view taken along line 3 3 in Fig. 2,assuming that the entire structure of the control valve assembly isshown in Fig. 2;

Fig. 4 is an enlarged cross sectional view taken along line 4-4 in Fig.2 again assuming that the complete structure is disclosed in Fig. 2; and

Fig. 5 is an enlarged fragmentary sectional view taken along line 5-5 ofFig. 4 assuming that the complete structure is shown in Fig. 4.

Referring now to the drawing wherein like reference numerals indicatethe same elements throughout the several views, and more particularly toFig. l of the drawing wherein is disclosed an oil burner systemutilizing the improved control valve assembly of this invention, an oilfilter 10 is provided with fuel oil from an external source (not shown).The filtered oil from the filter assembly l0 is drawn through a conduitor pipe l2 by a gear pump i4 and supplied through a conduit lo to achamber i7 in a unitary control valve assembly indicated generally aslli. The unitary valve assembly l, shown operated open in Fig. l,generally operates to provide a bypass nozzle 2t) having a swirl chamberZita with a flow of high pressure oil through a conduit 22, and alsoregulates the return of the fuel oil from the nozzle 2li through a pairof bypass conduits 2li and 26.

A fuel supply control valve assembly indicated generally as 28, aby-pass control valve assembly indicated generally as 30, and a pressureregulator indicated generally as 32 comprise the unitary valve assembly18. In order to provide an operation wherein the by-pass valve 30 isopened prior to the opening of the fuel sup'- ply valve 28 when the pump14 is started, the two valve assemblies 28 and '30 are interconnectedadjacent their upper ends by a yoke or plate 3dwhich is provided with apair of bearing elements 36 and 37 secured thereto. The upper ballbearing element 36 is resiliently urged in a downward direction by aspring loaded diaphragm assembly 33 of the pressure regulator 32 so thata pair of ball bearing valve elements 33 and 40 associated with thevalve assemblies 23 and 3@ are urged into engagement with the upper endsof the conduits 22 and 24 to close these conduits.

As the pressure of the fuel oil supplied to the assembly 1S isincreased, the diaphragm 33 is moved vertically upward so that a spring42 urges the valve assembly 30 in an upward direction to pivot or tipthe plate 3d in a clockwise direction about the right edge of the plate34 as a fulcrum, thereby to open the valve 3%. Continuing upwardmovement of the diaphragm 33 permits the plate 34 and valve assembly 2Sincluding the ball valve element to move upwardly and places the conduit2?.- in iluid communication with the supply of high pressure oil. lnthis manner, it is seen that the by-pass conduit 24 is placed in fluidcommunication with the by-pass conduit 26 and nozzle Ztl prior tosupplying high pressure oil to the fuel conduit 22 and nozzle 20 whenthe I pump 14 is actuated.

To provide the operation wherein the 1:3y-pass valve assembly 30 closesfollowing the closure of the supply valve assembly 2S when the pump l@is stopped, it is seen that a decrease in the pressure of the fuel oilsupplied by the conduit 1d to the assembly 18 permits the diaphragm 33tomove in a downward direction as shown in Fig. l. This downward movementof the diaphragm 33 moves the valve plate or yoke 3ft in a downwarddirection so that the two valve assemblies Zti and Stil movably carriedthereby are also moved in a downward direction. Since the valve assembly30 is spring loaded by virtue of the provision of spring (i2, the valveassembly 28 closes rst to cut olf the supply of oil to the nozzle Ztlwhereupon continuing downward movement or the diaphragm 33 under theforce of a spring 4.4 overcornes the resilient action of the spring l2to pivot the plate 34 in a counterclocltwise direction about its rightedge to seat the valve element 3@ with the upper extremity of theconduit 24 to close the bypass line from the J nozzle 20. ln thismanner, the invention provides a unitary control valve assembly 18wherein the fuel supply to the nozzle 2u is stopped before the by-passfrom 'this nozzle is closed.

In order to regulate the pressure of the fuel supplied to the nozzle 20after the valve assembly '2.1% opened, the pressure regulator 32includes an opening 46 located centrally of the lower portion of thediaphragm 33. As long as the pressure of the fuel oil supplied remainswithin the range of pressure desired, the ball bearing 36 closes theaperture d6. However au increase in pressure beyond the desired amountmoves the diaphragm in au upward direction and, since the upwardmovement of the yoke 34 is limited by shoulders 4S formed in the bodyportion of the assembly l, the aperture 46 is opened to permit a flow offuer oil to a by-pass reservoir 50 through a conduit 52 and a chamber d4formed in Vthe assembly 18.

The flow of oil from the oy-pass conduit 24 through the by-pass valveassembly 30 to the reservoir 50 is con" trolls-d by a needle valveindicated generally as 56 'cooperating with a passageway 57. Bycontrolling the flow of oil through the bypass line 24, it is possibleto regulate the back pressure to the nozzle 20. Obviously', the

needle valve 56 may be replaced by any well known 'type of pressureregulator valve.

The pressure lat which fuel oil is admitted to thc nozzle l2.0 and,consequently, lthepressure at which the plate 34.is moved yupwardlyunder the action of the spring 42 is controlled by adjusting theamountfof force applied by the coil spring 44 to the lower surface ofthe diaphragm 33. The pressure applied by the coil spring 44 is adjustedby means of a machine screw 60 threadedly engaged within a cover plate62, the lower end of which is in engagement with a plate daly having anannular depending flanged edge within which the upper convolution of thespring 44 is received. The force of compression applied by the spring 44also regulates the pressure at which the valve forming ball bearing 36is moved out of engagement with the aperture 46 to permit the ow of fueloil therethrough when the pressure of the fuel oil exceeds that at whichit is desired to supply the nozzle 20.

The control valves 28 and 30 are provided with high seating pressures bythe coil spring 44 since the force thereof is applied to the ballbearing valve elements 38 and dil through the bearing valve element 36,plate 34, and the plungers 28a and 30a in the respective valveassemblies 28 and 30.

Figs. 2 to 5, inclusive, disclose a unitary valve assembly 7b similar tothe assembly 18 and which includes apressure regulator 72, a by-passcontrol valve 74, and a fuel supply control valve 76. The two valveassemblies '74 and 76 are removably positioned in a valve plug 78 whichis threadedly received within a body portion or frame The `upper ends ofthe two valve assemblies are movably and mechanically interconnected bya valve control plate S2 (Fig. 5) to produce sequential operation of thetwo valve assemblies in a manner similar to that described inconjunction with the sequential operation of the two valve assemblies 28and 30.

The valve assembly is adapted to be connected to a source of highpressure fuel oil through a passageway bal within which may be receivedthe supply conduit 16 so that a chamber S6 formed in the body 80 isprovided with fuel oil under high pressure from the pumping means i4.r)The fuel supply valve assembly 76 is provided with a counterbore Seformed in the plug 73 to receive the nozzle fuel supply conduit 22, andthe by pass control valve assembly 7d is provided with a counterboreadapted to receive the by-pass conduit 24.

To produce the sequential operation of the valve assemblies '74 and 76,the high pressure fuel oil within the chamber 86 ows through an aperture92 formed in the upper end of the plug 78 into a counterbore 94, alsoformed in the plug 78, as best shown in Fig. 5. When the oil pressurereaches the magnitude at which it is .desired to supply fuel oil to thenozzle A20, the fuel .oil produces an upward movement of a flanged cap96 comprising the lower wall of a diaphragm assembly 98 .c of thepressure regulator 72. The valve control plate 82 having an upstandingportion lill) to which a ball valve .element 102 is secured isresilientl-y urged into engagement with the cap 96 vby means of a coilspring 103 interposed between a sleeve 104 (Fig. 2) and a shoulderformed on a valve control plunger 106 in the by-pass control valveassembly '74. The resilient action of the spring i103 is transmitted tothe ball bearing 102 through the plunger 106 and the control plate 32which is movably secured tothe plnger 106 by means of a pin 108 securedto the plunger (Figs. 2 and 4) and a somewhat larger slot 110 formed inthe plate 82.

Upon upward movement of the cap 96 under the action of the high pressurefuel oil, the plate S2 tips in a clockwise direction ('Fig. 2) about afulcrurn point provided adjacent the right hand extremity of the plate82. A pair of bearings 112 secured to a bottom vsurface of the plate 32,which prevent skewed deflection of the plate 82, are also lifted out ofengagement with the upper surface of the counterbore 94 by this tippingmovement. This clockwise tipping of the valve control plate .82, asviewed in Fig. 2, opens the by-pass by mov ing a valve forming ballbearing 113 out 0f engagement with the sleeve 104 ito'open fluidcommunication between the counterborc i90 of the by-pass line and anannular cavity114forrned inthe body 80 through a passageway 116 in theplug 78. It should be noted that the clockwise tipping of the controlplate 82, while opening the valve assembly 74, maintains the highpressure inlet valve assembly 76 in a closed condition.

The fuel supply valve 76 is next opened by continued upward movement ofthe cap 96 under the control of the high pressure fuel oil since theplate S2 moves in an upward direction and tips in a counterclockwisedirection to lift a plunger 118. This plunger is movably secured to theplate 82 by means of a pin 120 (Fig. 4) and slot 122 and in movingupwardly lifts a valve forming ball bearing 122 (Fig. 2) secured to theplunger 118 out of engagement with a sleeve 124.

This opening of the valve 76 places the high pressure fuel oil in thechamber 86 in uid communication with the nozzle 20 through a uid circuitcomprising the passageway 92, the counterbore 94 and apertures 125 inplate 82, a slot 126 formed axially of the plunger 118, the innerpassageway of the sleeve 124, counterbore 88, and conduit 22.

To provide for regulation of the pressure of the fuel oil supplied tothe nozzle 20, the plate 82 is limited in the amount of allowable upwardmovement by an annular ring 128 secured to the inner surface of thecounterbore 94. Continuing upward movement of the cap 96, due to anincreased pressure of the fuel oil supplied by the pump 14, results inthe disengagement of the valve forming `ball bearing 102 with apassageway 130 formed centrally `of the cap 96. lUpon disengagement ofthe bearing 102 with the passageway 130, fuel oil passes to the by-passreservoir 50 through the diaphragm assembly 98 and the conduit 52 whichis in huid communication therewith.

The fuel oil by-passed from the nozzle 20 and returned to the valveassembly 70 by the `conduit 24 passes upwardly through the counterbore90 and the inner kcavity of the sleeve 104 and thence through thepassageway 116 to the annular cavity 114. The oil in the cavity 114 isreturned to the by-pass reservoir 50 through a passageway 130 andvertically extending chamber 132 which is in fluid communication withthe by-pass conduit 26. The iiow of fuel oil from the cavity 114 throughthe passageway 130 is controlled by a ow adjusting screw 134 which isthreadedly engaged within a` chamber 136 formed in the body 80. An outerportion of this flow adjusting screw is received within a packing gland138 to prevent oil seepage along the outer surface of the screw 134, anda centrally recessed cap screw 140`also `threadedly received within thebody 80 covers `the adjusting end of the screw 134 to prevent anyundesired interference with a predetermined adjustment of the screw 134.Obviously, the ow adjusting screw 134 and its associated elements may bereplaced by anyone of the well known pressure regulator valves.

A coil spring (Fig. 2) 142 resiliently urges the diaphragm assembly 98and cap 96 downwardly into engagement with the ball bearing 102 and,accordingly, controls the pressure at which fuel oil is admitted to thenozzle 20, and, consequently, the pressure at which the pressureregulator72 operates to by-pass a portion of the fuel oil in the chamber86 to the by-pass reservoir 50. Any suitable means, for instance, thatdisclosed in Fig. l of the drawing, may be utilized to regulate theresilient action exerted by the spring.142 on the` movable diaphragmassembly 98.

When the pressure of the fuel oil in the chamber 86 is decreased, asproduced by stopping the pump 14, the cap 96 moves downwardly as viewedin Figs. Zand 5 to move the valve control plate 82 in a correspondingdirection. To provide a closure of the fuel supply control valve 76prior to the closure of the by-pass control valve 74, the downwardmovement of the left hand `portion of the plate `82 is retarded by thespring biased tinuing downward movement of the cap 96,'thereby to rstdepress the plunger 118. Thisl downward move# ment of the plunger 118seats the bearing valve element 122 on the sleeve 124 to cut olf uidcommunication between the nozzle 20 and the high pressure fuel oilsupplied by the pump 14. A continuing downward movement of the cap 96under the resilient action of the spring 142 overcomes the retardingforce provided by `the coil spring 103 and the plate S2 pivots about thefulcrum provided by the seated plunger 118 to seat the bearings 112 onthe upper surface of? the counterbore 94 and to seat the bearing valveelement 113 on the sleeve 104 to close tluid communication between theby-pass reservoir 50 and the by-pass conduit 24,.

The valve assemblies 74 and 76 are capable of utilizing high seatingpressures upon being closed inasmuch as the force of the coil spring 142is transmitted through the cap 96. ball bearing 102, plate 82, andplungers 106 and 118, to the valve bearing elements 113, and 122,thereby to cause these elements to seat firmly against the cooperatu ingsleeves 104 and 124. Also, the valve assemblies 74 and 76 must operatein the desired sequence in View ofthe positive biasing and retardingaction provided by the coil spring 103 associated with the by-passcontrol valve assembly 74.

ln operation, the pump 14 is actuated to supply fuel oil to the valveassembly 70 through the filter member 10 and conduits 12 and 16. Whenthe oil pressure builds up to the point at which the cap 96 is movedvertically upward, as shown in Fig. 2, the by-pass control valveassembly '74 is opened first because of the biasing action ot' the coilspring 103. Subsequent thereto, continuing upward movement of the cap 96allows the control plate 82 to move upwardly into engagement with theretaining ring 128 whereupon the plunger 118 is moved upwardly to unseatthe bearing valve element 122. The oil in the chamber 86 then passes tothe nozzle 20 through passageway 92, counterbore 94, slot 126,counterbore 88, and conduit 22. The by-pass o-il from the nozzle 20 isreturned to the by-pass reservoir through conduit 24, passageway 116,chamber 114, passageway 130, chamber 132, and conduit 26.

When it is desired to stop the operation of the oil burner system,actuation is removed from the pump 14 to produce a correspondingdecrease in the fuel oil pressure within the chamber 86. This decreasein pressure permits the cap 96 to moved downwardly under the forceapplied by the spring 142 to move the bearings 112 into engagement withthe upper surface of the counterbore 94. Continuing downward movement ofthe cap 96 moves the valve bearing element 122 into engagement with. thesleeve 124 to prevent a flow of oil to the nozzle 2t).l A furthercontinuing downward movement of the cap 96 tips the valve control plateS2 to depress the plunger 1116 against the retarding action of thespring 103 to firmly seat the valve bearing element 113 in engagementwith the sleeve 104 and thereby close oi fluid communication be tweenthe try-pass reservoir 5'@ and the by-pass conduit 24 associated withthe nozzle 20.

The above described embodimentsare merely illustive of the principles ofthis invention and numerous other modifications may be devised by thoseskilled in the art which fall within the spirit and scope thereof.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

l. Apparatus for use with an oil burner system utiliz`- ing a fuelsupply line to and a by-pass line from a nozzle, comprising, a unitaryvalve assembly for controlling the ow of fuel oil through both of saidlines, said valve assembly comprising control valve means forcontrolling 'the passage of fuel through each of said lines, pivotallysupported means interconnecting said control valve means, and meansresponsive to the pressure of the oil to be supplied to the nozzle lfortipping the pivotally supseroit mesas t@ what@ the Qontrol valve meansin a Ptsdst las@ sequence in acordance with the pressure of the .01.1.

1?.. Apparatus for use with an oil burner `system utilizing fuel supplyline to and a return line from a nozzle, comprising a unitary valveassembly for controlling the ow of oil through both of said lines, saidassembly comprising a control valve in each of said lines, one of saidcontrol valves being resiliently urged toward an open position,operating means interconnecting the two control valves, and a pressureresponsive means in cornmunication with thc oil to be supplied to thenozzle and in engagement with the operating means to actuate theoperating means to open the resiliently urged valve and then the othervalve in response to an increase in the oil pressure.

3. The apparatus defined by claim 2 in which the resiliently urged valveis connected to the return line.

4i. The apparatus deined by claim 2 in which the pressure responsivemeans .normally hold-s both of the valves in u closed condition.

5. Valve apparatus comprising body deiining a chamber, pressureresponsive by-pass valve means mounted in chamber, a movably mountedrigid plate positioned in said chamber in engagement with said pressurerespon- `sive moans, a pair of independent valve means operativelyconnected to said plate, and means for introducing fluid under pressureinto said chamber whereby said pressure responsive means moves saidplate to operate said valves.

6. The apparatus defined by claim 5 in which the plate is rcsilientlyurged toward said pressure responsive means.

7. `v'alve apparatus, including in combination, a body defining achamber and a by-pass passageway, pressure regulating means having a rstvalve adapted to place said chamber and said passageway in fluidcommunication, second valve means, and valve operating means movablymounted on said body with said operating means iu a force transmittingrelation with said regulating means for operating said `second valvemeans, said force transmitting relationship maintaining said. firstvalve closed, said regulating means and said operating means beingmovable in said force transmitting relationship to operate said secondvalve means, said regulating means and said operating means also beingmovable out of said force transmitting relationship whereby said firstvalve places said chamber and said oy-pass in. iiuid communication.

8. A unitary pressure regulator and valve operator for use in systemsutilizing fuel supply, return and bypass lines comprising a body deninga chamber, fluid pressure regulating means having lirst valve means -iniiuid communication with said chamber and said by-pass liuc, said iirstvalve means being closed over a first range ot pressures and open toby-pass iuid to said bypass line from said chamber in a second liuidpressure range, second valve means for controlling the ilow of fluidthrough said supply and return lines, valve operating means movablymounted on said body and actuated by said regulating means through saidfirst pressure range to actuate said second valve means, and means foradmitting liuid having a pressure in said ,rst and second ranges to saidchamber.

9. The apparatus deiined by claim E in which an in crease of pressure insaid irst pressure range actuates said second valve means to open saidreturn line and thereafter to open said supply line.

l0. The apparatus deiined by claim 8 in which a decrease of pressure insaid irst pressure range actuates said `second valve means to close saidsupply line and thereafter to close said return line,

l1. The apparatus defined by claim 8 in which the body is formed withmeans placing the chamber in liuid communication with the supply line.-

12. Valve apparatus, including in combination, a body (leuning a chamberhaving a fluid inlet and an opening,

said opening including detachable connecting means, preslil) 5i sur@responsive means in. Said chamber and in Huid .Ceorpunication with saidinlet, and an insert velement cluding valve means and valve operatingmeans controlled'by saidpressure responsive means, said insert elementbeing mounted in said opening by said detachable connecting means.

13. A control valve for use in a fuel oil burner system, comprising, abody defining a chamber, a fuel supplyport opening through said bodyinto said charnber, a bypass conduit through said body, a valve disposedwithin said chamber for controlling the passage of iiuid between saidchamber and said bypass conduit, a pres* sure responsive membercommunicating with said chamber for actuating said valve in response tothe pressure in said chamber, a nozzle fuel supply passageway in saidbody communicating with said chamber, a fuel supply valve supported bysaid body and positioned to control the flow of fuel from said chamberto said passageway, a nozzle bypass duct through a portion of said body,la nozzle bypass valve in said duct for controlling the passage of fueltherethrough, spring means associated with said nozzle bypass valve forbiasing it in an open position, and a valve operating member actuated bysaid pressure responsive member for sequentially opening said lastnamedvalves, said spring being operative to maintain said bypass valve openat a chamber pressure less than that required to actuate said valveoperating member to open said fuel supply valve.

14. A iiuid control valve comprising a body having a pressure chamber, aport for the emission of pressurized iiuid into said chamber, a bypassport for returning excess fuel from said chamber to a reservoir, anozzle supply port in said body for conducting fuel from said chamber toa fuel nozzle, a nozzle bypass port in said body for returning fuel fromsaid nozzle, a valve in the bypass port, a valve in the nozzle supplyport, a valve inthe nozzle bypass port, means including a flexiblediaphragm for sequentially controlling the passage of fuel through eachof said ports as the fuel pressure in said chamber varies throughout apredetermined range, and means for supplying a biasing force to saidnozzle bypass valve to urge it toward an open position thereby to insureopening of said bypass port at a chamber pressure less than thatrequired to open said nozzle supply port.

l5. A fluid control device comprising a body having a pressure chamber,an inlet port, a nozzle supply port and a nozzle bypass port, a valvecontrolling said supply port, a valve controlling sadi bypass port,means for normally urging said valves into positions to close saidports, a flexible diaphragm in said chamber for urging said means out ofoperative engagement with said valves when the pressure in said chamberexceeds a predetermined value, and means acting on said valvecontrolling said bypass port in opposition to the force exerted thereonby said lirst-named means, whereby said bypass port is opened at achamber pressure less than that required to open said supply port.

i6. Apparatus of the type described, comprising, a body having apressure chamber, an inlet port to said chamber, an outlet port fromsaid chamber, a valve controlling said outlet port, a nozzle bypass ductthrough said body, a nozzle bypass valve controlling said bypass duct,an operating member secured at spaced locations to an operating elementof each of said valves, means exerting a force on said operating memberto porrnally close said valves, means exerting a force on only one ofsaid valves in opposition to ,the force exerted thereon by said rstnamed means, and pressure responsive means disposed in said chamber forcounteracting the force exerted on said operating member by said firstnamed means when the pressure in said chamber exceeds a predeterminedvalue.

17, A control valve for oil burners, comprising, a body having 'apressure chamber, an inlet port to said chamber, a bypass port 4forreturning fuel from said chamber to a reservoir, an outlet port forconducting fuel from said chamber to a fue] nozzle, and a nozzle bypassduct for returning fuel from said nozzle to said reservoir, a valve forcontrolling the flow of fuel from said chamber to said bypass port, avalve for controlling the flow of fuel from said chamber to said outletport, a valve for controlling the ow of fuel through said nozzle bypassduct, a flexible diaphragm positioned in said chamber and responsive tothe pressure of the fuel in said chamber for opening each of saidvalves, resilient means for normally urging said nozzle bypass valveinto an open position, and means for normally urging each of said valvesinto a closed position.

18. A unitary control means for use with a burner system including botha fuel supply and a fuel supply line to and a bypass line from a nozzlecomprising a chamber provided with fuel under pressure from said supply,independently movable valve means for controlling the passage of fuelthrough each of said lines, pressure responsive means positioned withinsaid chamber to be controlled by the pressure of the fuel therein, and amechanical link operatively connected to the pressure responsive meansincluding separate means movably connecting each of the two valve meansto said link to operate one of said valve means and then another of saidvalve means in a predetermined sequence under the control of changingfuel pressure.

References Cited in the file of this patent UNITED STATES PATENTS1,841,140 Murphy et al. Ian. l2, 1932 2,032,284 Johnston Feb. 25, 19362,193,075 Osborne Mar. 12, 1940 2,494,714 Lyman Jan. 17, 1950 2,604,149Wynne July 22, 1952

